Carburetor



E. F. GEIGER Aug. 18, 1931.

cmaunmon Filed March 27, 1928 Patented Aug. 18, 1931 EDWARD r. GEIGER,OFIBINGHAIMTON, NEW YORK CARIBURETOR' Application filed March'27, 1928.Serial No. 265,133.

The present invention relates to improvements in carburetors and moreparticularly relates to a provision of a carburetor which is adapted toprovide an automobile engine with the proper quality of fuel mixture atvarious and all engine speeds and when the engine operates underdifferent power requirements.

More particularly the present invention relates to an improvement andmodification of the carburetor disclosed in my copending applications,Serial No. 105,668, filed April 30, 1926 and Serial No. 17 6,097 filedMarch 17, 1927. I

According to the present invention the quality of the fuel mixture iscontrolled primarily by the degreeof throttle opening and secondarily bythe air speed through the carburetor, so that for low air speeds themixture will be rich or lean depending upon the extent to which thethrottle is opened and with widely open throttle conditions the mixturewill be rich or lean dependin upon whether the air speed is low or high.buch ultimately desired results while heretofore obtained with my formerconstructions necessitated the use of supplementary movable auxiliaryvalve means which, according to the present invention are dispensedwith.

The present invention provides a novel cooperation of parts including aventuri disposed in a. novel manner which parts and .vcnturi cooperateto produce the desired quality of mixture under-varying conditions ofengine operation.

Further objects and advantages will be hereinafter set forth in theaccompanying specification and claims shown in the drawings, which by waof illustration show what I now consider to be a preferred embodiment ofthe invention.

In t 1e drawings:

Figure 1 shows substantially a central vertical sectional view of mycarburetor with a sectionalized.

Fig. 2 is a large sectional detail View like Fig. 1 showing theaforesaid tube in central section.

the upper part of 11. certain tube therein shown in full and not Fig. 3is a detail end view taken on line 3-3 of Fig. 1.

The carburetor comprises the usual well known parts such asmanifold-connection 1 having associated therewith a mixture con- 65 duit2 provided with a throttle valve 3 0perated in the usual manner. Thisvalve 3 has certain novel features of construction which will behereinafter described The carburetor also includes a convention alconstant level float chamber 4 which is supplied with fuel through pipe5, the flow of fuel being controlled by float valve 4a.

There is furthermore provided an air inlet conduit 6, extending belowthe throttle and provided with the usual choke Valve 7. Disposed in theconduit 6 intermediate the choke 7 and the extended portion 2a of themixture conduit 2 at a point below the throttle 3, is a venturi 8 whichserves as will hereinafter be described.

Extending substantially centrally through the float chamber 4 is a uelwell 9 having a tubular outer wall 9a. This fuel well 9 is supplied withfuel from the float chamber through a calibrated orifice 10. Within thetube 9a is a tubular conduit 11 provided with a plurality of calibratedpassages 12 through its wall, which passages establish communicationbetween the fuel well 9 and a space inside of conduit 11. Extending intoconduit 11 and closing its lower end preferably by being press fittedtherein is another conduit 13. This conduit is open at both ends andserves to conduct air into conduit 11 at a point above the normal levelof the fuel therein as shown in Fig. 2. The throttlevalve 3 is slottedas shown at 14, this slot affording an opening from the space 2 to thespace 2a below the throttle. A screw adjustment 15 is provided adaptableto be manually manipulated for setting the total effective area of theopening or slot 14. A conduit 16 forms a continuation of conduit 11 andclosely fits The conduit 16 extends up towards and al" most reaches thethrottle valve 3 when the latter is ina nearly closed position as shownin Fig. 1. The upper end of conduit 16 is fur thermore shaped orbevelled to substantially a special purpose 70 shown. The throat of theVenturi section 8 is in communication with the fuel well 9 at a pointabove the normal fuel level. Such communication is afforded by passages17 annular chamber 18, passage 19 and chamber 20. Chamber 20 furthermorecan be connected to atmosphere. An opening 21 is provided in the wall ofchamber 20 and a screw adjustment 22 is provided which can be set to anydesired position to vary the total effective area of opening 21. TheVarious parts and passages 16, 13, 21, 20 and 9?) all constituteauxiliary air passages and conduits for supplying air additionally tothat supplied through the main air conduit 6. All of such auxiliary airfinally enters the mixing chamber through conduit 16.

In operation, the action of the carburetor is different with differentdegrees of throttle opening. \Vhen the throttle is in a nearly closedposition the suction of the engine produces a considerable depression orlowering of the pressure in the mixture conduit 2 above the throttle.There is, accordingly, a resultant high air speed through the opening14. Due to the location and arrangement of conduit 16 this high airspeed brings about a depression of pressure within conduit 16. theeffect of which is to produce a rush of air up through conduit 13,through 11 and into 16. A pressure differential is also created betweenthe inside of tube 11 and the space 9?) outside of such tube. Thispressure differential causes air to pass through the upper openings 12above the fuel level in well 9 into the interior of tube 11. Thepressure differential will also cause fuel to flow through the lowersubmerged openings 12 into 11. As such fuel flow proceeds through theseopenings, the withdrawal of fuel will cause the level of the fuel inwell 9 to fall uncovering more of the openings 12 and causing the airpassing through such uncovered openings to mix with the fuel in annularspace 30. This fuel or mixture upon passing upwardly beyond the top oftube 13 becomes commingled and atomized with the air which flows upthrough 13. The atomized fuel and air is carried along through conduit11 through 16 and opening 14 into the mixture chamber 2 where themixture is commingled with any air which may pass the edges of thethrottle provided the throttle is very slightly opened. In this way thefuel mixture is formed for the engine when the latter is idling orrunning with a nearly closed throttle.

As previously stated. air is drawn through some of the upper openings12. i There is ac cordinglv, a lowering of the pressure in chamber 20which chamber is in communication with the space 9!). On account of thislowering of pressure, air flows into chainber 20 through opening 21.Furthermore, because under nearly closed throttle conditions, there is arelatively small movement of air through the main air intake 6, thepressure at the throat of the venturi 8 is practically atmosphericpressure and consequently under this condition air also may flow intochamber 20 through the passage 19 from the interior of the venturi. Thisflow of air into chamber 20 through passage 19 and opening 21 issufficient to keep the lowering of pressure in chamber 2 0 andconsequently in the fuel Well space 96 very small, so that under theseoperating conditions very little fuel will be caused to flow into thefuel well 9 through passage 10 due to the depression in pressure in 9?).As fuel is drawn out of the fuel well 9 through passages 12 the fuellevel in the well 9 will be lowered until sufficient gravity head isestablished between the fuel level in 9 and in the float chamber 4 tocause fuel to flow into 9 through the calibrated orifice Operation underwide open throttle conditions at low engine speeds Vith the throttle inwide open position, the full suction induced by the engine is throwndirectly upon the main intake 6 and upon tube 16. The strong rush of'air induced through 6 produces a considerable drop of pressure at thethroat of the venturi 8. Such drop is communicated through passages 17,18 and 19 to chamber 20 and thus acts to modify the pressure conditionstherein. 'The pressure conditions in this chamber are also controlled bythe port opening 21. The ultimate resulting depressed pressureconditions in chamber 20 are communicated to space 96 and there act tocause the drawing into the fuel well 9 of fuel at a rate which iscoordinated to the air speed through the venturi.

It will be remembered that under the previously described operatingconditions there was practically no depression of pressure in 9/) andaccordingly the fuel is supplied to the well 9 at a comparatively morerapid rate through duct 10 when there is a greater depression of thepressure in 91) than when there is practically no depression of pressure in such space 97). However, it must be remembered that there is acomparativelyrclatively greater depression of pressure in space 30. Theeffect of this is notwithstanding the relatively greater flow of fuel towell 9. to remove the fuel more rapidly therefrom and to lower the fuellevel in space 9 to a relatively loWer point. The ultimate result isthat the fuel gravity head is available in addition to the suction .inspace 96, to induce the fuel flow through 10 into the well andultimately secure a relatively rich mixture for running with wide openthrottle at ,low engine speeds.

Operating with wide open throttle with high engine speeds With highengine speeds, the foregoing operating conditions and effects aremodified in this manner. The fuel gravity head remains. as beforebecause the fuel level in well 9 cannot be lowered any further or beyondthe lowermost opening 12. \Vith such gravity head remaining constant,the increase in fuel flow is brought about only by the increase inVenturi suction. The dimensions of the venturi 8 are such thatsuchventuri acting alone will not produce the required richness ofmixture and the suction produced by this venturi must be supplemented bythe head of the fuel in constant level of the fuel reservoir 4. Atrelatively lower air speeds the fuel head from 4 is dominant withrespect to the suction head which is available from the venturi but asair speeds increase the suction from the venturi becomes pre-dominantwhile the'fuel head from 4 remains fixed. The ultimate action is thus toprovide a relatively leaning out of the mixture as air speeds increase.To further explain this leaning out action, reference will be made to anillustrative example. For purposes of illustration and explanation onlyassume that the fuel head in 4 to be 1 inches of water and that thesuction produced by the venturi 8 for a certain air speed to be 2inchesof Water. Accordingly, the result of the total head which isavailable for the flow of fuel is that of the sum of tWo or 3 inches 'ofwater. Now assume that the air speed through 8 is doubled, thusproducing for example, a Venturi created suction of 4 inches of water.The fuel head from 4 remains constant at 1 inches. The sum of 4 plus 1inches equals 5% inches which lacks 1% inches of being double in theinitial total head Whichwas previously available, i. e. 3.5 times 2equals 7 which equals 5 plus 1 Thus the 1 inches of water representsrelatively the amount of leaning out of the mixture which is obtained asthe air speed increases. The ultimate result is a progressive leaningout of the mixture as the engine speed increases with the throttle inwide open position.

It will be understood that the su'tion produced by the venturi in space97) should not be permitted to reach the suction produced in tube 11. Ifsuch an effect took place the fuel-level in 9 would-rise until itdischarged fuel into chambcrQO. Such undesired action is prevented bythe port 21 which insures Operating with throttle in intermediate po.si

tions and normal running speeds" It will be assumed that valve 3 is opensay 20%. Under these conditions the rush of airpast the throttle will bemostly around the edges of the throttle which points are somewhat remotefrom the end of conduit- 16. Under these conditions also the slot 14will be so far displaced from the end of the conduit 16 as to have'itseffect of inducing air flow through the conduit 16 much reduced. Theultimate result is to induce a relatively less depression of pressure in16 than would be induced therein with the same air speed through thecarburetor and with the throttle valve in wide open position. Under wideopen conditions as before explained the full suction of the engine iseffective upon the tube 16 and the velocity of the air as it rushes pastthe tube at its periphery augments this suction. Accordingly thedepression in 16 is relatively less with relatively closed throttlepositions.

The ultimate pressure in chamber 20 and 9?) depends upon the action ofthe venturi and the Withdrawal of air from the chamber through ports 12.lVith the relatively less depression of pressure in 16 and 11 relativelyless air will be withdrawn through the ports 12 from 96 and 20. tivelyless effective suction in 9b and accordingly relatively less rapidwithdrawal of fuelfrom 4 through 10 into 9. Accordingly the fuel mixturewhich is produced under these conditions is relatively lean.

If the engine speed varies under the foregoing conditions the venturiwill cooperate to vary the amount of fuel which is supplied.

Sun'imarizing it may be mentioned that the present carburetor is of theso-called plain tube type and it is also incorporates a Venturi devicedisposed in a novel location.

\Vhat I claim is:

1. A carburetor having therein an air intake passage. avcnturi, a mixingchamber.

This will result in relabeing disposed in the air intake at a pointahead of all of the fuel supplying means.

2. A carburetor of the straight tube type and including in combinationwith fuel supplying tube parts of the carburetor, an air intake, aventuri disposed remote from said fuel supplying tube parts and in theair intake, and means'including passages leading into the venturi andconnected with the tube parts for modifying the fuel supplying actionof'said tube parts by varying the pressure conditions therein inaccordance with the air speed through the main air intake and saidventuri.

A carburetor with a mixture outlet and an air intake, a venturi therein,a fuel well subject to the suction of said venturi and connected to themixture outlet at a point entirely beyond the venturi so as to supplyall the fuel mixture at such point, a throttle valve, and means formodifying the suction etfect of the venturi upon the fuel well inaccordance with the degree of throttle opening, said mentioned meansincluding a passage for the fuel from the fuel well to the mixtureoutlet of the carburetor.

4. A carburetor with an air intake, a venturi disposed therein, a fuelwell subject to the depression produced by said venturi, a throttlevalve, a conduit adjacent said throttle valve and disposed so that thedepression produced in said conduit by the suction of the engine isvaried by the degree of opening-of the throttle, means for supplyingfuel through the conduit which extends adjacent the throttle for allrunning condiions including wide open throttle conditions, means forcommunicating said depression in said conduit to the fuel well and formodifying the depression therein induced by the aforesaid venturi.

.3. A carburetor with a fuel well from which fuel is supplied to amixture outlet, said fuel well being adapted to supply all fuel throughsaid outlet which is required for all the various operating conditionsof the carburetor, and means for subjecting said fuel to variousoffsetting pressure effects, said means including a venturi in thecarburetor air intake to provide one pressure effect and a conduitextending adjacent the throttle for providing another pressure effect.

6. A carburetor with a main mixture conduit, and an auxiliary airconduit leading thereinto. and means for supplying fuel to the auxiliaryair conduit, a throttle valve in the main mixture conduit andcooperating with said auxiliary air conduit to cause the flow of airthrough the main mixture conduit by its velocity heads to supplement thedepression of pressure induced in the auxiliary ai-r conduitby thesuction of the engine.

I. A carburetor provided with a mixture outlet, an air intake, a venturidisposed therein, a throttle valve, a supplemental conduit adjacent saidthrottle valve, said throttle valve cooperating with the end of said supplemental conduit so that an increase in the degree of throttle openingwill cause the engine suction and the velocity head induced by the rushof air from the air intake past the supplemental conduit to produce anincrease in the depression in said supplemental conduit, a fuel wellassociated with the aforesaid supplemental conduit and in communicationwith the venturi so as to be subject to the depression induced asaforesaid in said supplemental conduit and induced in the venturi, andmeans admitting fuel from the fuel well through said conduit to themixture outlet of the carburetor.

8. A carburetor of the straight tube type with an associated fuel well,an auxiliary air conduit opening at one end directly to the atmosphereand receiving the fuel, and a supplementary means for controlling thefuel supplying action from said well, said means comprising a venturicapable of receiving air only disposed in the air intake conduit of thecarburetor and having passages connected to the fuel well to adjust thepressure therein according to the flow of air through the venturi, theaforesaid auxiliary air conduit of the carburetor being disposed at apoint beyond the venturi.

9. A carburetor having an air intake, a venturi in said intake adaptedto receive air only, a fuel well connected to deliver fuel mixtureentirely beyond the venturi and passages connecting the throat of theventuri t0 the fuel well for the purpose described.

10. The invention set forth in claim 9 in which a controlled port isprovided from the atmosphere to said passages for modifying the suctioninduced by the venturi.

11. A carburetor having a mixing chamber, an air intake, a throttlevalve, and provided with a fuel well with means for deli vering from thefuel well into the mixing chamher all of the fuel mixture which isrequired for all operating conditions of the carburetor and including incombination, cooperating suction inducing means which produce anultimatesuction upon the fuel in the well which is the resultant ofseveral suction effects, such suction inducing means including a venturiin the air intake for inducing one suction effect upon the fuel in theWell in accordance with the air speed through the air intake and intowhich venturi air only can flow, said suction inducing means alsoincluding a conduit extending in proximity to the throttle for inducinganother suction effect upon the fuel in the Well in accordance with thedegree of throttle opening.

12. A carburetor having therein an air intake passage, a venturi, amixing chamber which is in unrestricted communication with the open endof the venturi, means for supplying fuel and air to said mixing chamber,a passage connecting the venturi with the aforesaid means to properlyproportion the fuel and air which is supplied to the mixing chamber,said venturi being disposed in the air intake at a point ahead of all ofthe fuel supplying means.-

13. A carburetor having therein an air intake passage, a mixing chamber,a 'venturi having one end opening into communication with said mixingchamber through a main air passage, means ,for supplying fuel and air tothe said mixing chamber, and passages supplemental to the main passageconnecting the venturi with the mixing chamber Which connect the venturiWith the aforesaid last mentioned means to properly proportion the fueland air which is supplied to the mixing chamber, said venturi beingdisposed in the air intake at a point ahead of all of the fuel supplyingmeans.

11 testimony whereof I hereto aflix my signature.

EDVVAR-D F. GEIGER.

